Thermotropic homopolyesters prepared from 4,4'-dihydroxybiphenyl and aliphatic diacids with a carbon number of 6-12 have been shown to exhibit high liquid crystallinity. See A. Blumstein, et al. Polymer 23:47 (1982); J. Asrar et al. J. Polym. Sci. Polym. Phys. Ed. 21:1119 (1983).
While these homopolyesters demonstrate an obvious liquid crystalline phase, they are too brittle to be used as high quality thermoplastics. The brittleness is attributable to high crystallinity. Thus, it is desirable to reduce the crystallinity of such polymers and thereby enhance their toughness.